INSITU AND SLOT HYBRIDIZATION ANALYSIS OF RNA IN COLORECTAL TUMORS AND NORMAL COLON SHOWS DISTINCT DISTRIBUTIONS OF MITOCHONDRIAL SEQUENCES

cDNA clones of mRNAs with an abnormal abundance in familial adenomatous polyposis were used to examine the levels and distribution of the mRNAs in tissues from 15 patients with colorectal cancer. Of 12 cloned sequences studied by slot hybridization, one was substantially reduced in tumours compared with normal tissue. Sequence analysis showed this to code for IgA. In situ hybridization was consistent with slot hybridization and immunohistochemistry. Two mitochondrially encoded sequences had distinct distributions detected by in situ hybridization but did not have detectable quantitative differences in whole tumour or mucosa extracts.